Okay, I'm not actually a press photographer. However, I just ran into this article (via dpreview) calling for the boycott of a concert because of contracts that deny photographers much of their exclusive rights, including serious restrictions on press usage, on photographs taken of the band at the concert. What rights do press photographers have, at least in the US and UK? Is this kind of press usage protected by law?
Caveat: I'm not an attorney, blah, blah.
Your rights with respect to the image may not be as important as your agreement with the venue. If you agree with the venue as a term of attending to behave in a certain way and you don't, then they might have an issue with you. So let's assume you attended a concert and they announced that no photography or videography of any kind is permitted during the concert (a common practice).
Now, at this concert, you decide to ignore the venue's stated rules of conduct and take some photographs. Technically, because you probably don't have property or model releases, you should be able to use the image in editorial contexts. However, because you were violating the venues request with respect to allowable activities, I can see how they might have a legitimate gripe.
Short story: If you start boycotting concerts because they don't allow photography, prepare yourself to attend fewer concerts. Lesser-known acts tend to be less picky so if concert photography is the itch you want to scratch, try them.
It should be noted that most of the calls about rights in public places don't apply to a concert, because it's a private event in a private space where access is granted on the terms of the event producers. you can't walk into an event like that and demand your rights, because the rights are what's granted you by them.
Different if this is an outside event in an open space like a park, but anything that requires a ticket has different rules than the "public access" rules.
So yes, a concert can require you to sit in the pit and only shoot pictures for the first three songs and apply limits on how you can use those pictures. you either accept those, or you don't get your press pass...
In the UK, the general position is that if you're in a public place, you can take a photo of whatever you like. This is independent of whether you happen to be a member of the press or just Joe Public, and also independent of whether the subject of your photo is on private land or not. You're not going to find an actual reference to this in UK statute because UK law (in almost all cases) restricts what you can't do, rather than saying what you can do. However, Wikipedia strongly supports the position I've outlined:
There are the usual bunch of exceptions around things like photography in court, of military bases and so on. There was a significant amount of fuss around Section 44 of the Terrorism Act 2000 which police attempted to use to prevent the filming of police officers, but this was ruled illegal by the European Court of Human Rights in 2010 and repealed.
If you're on private land, the question is under what rights you entered the land. As a landowner, I would be perfectly within my rights to say "you may not take photos while on my property", which is how concerts and the like get to choose what people may do with photographs taken at the concert.